Method and device for detecting a blood glucose level using a electromagnetic wave

ABSTRACT

The present invention provides a method for detecting a blood glucose level of a subject using an electromagnetic wave. Because a different blood glucose level is accompanied by a different electromagnetic absorption constant, the present invention compares a detected blood glucose electromagnetic absorption constant of the subject with data in a blood glucose electromagnetic absorption constant database so as to obtain a blood glucose concentration of the subject. The present invention also provides a device for detecting a blood glucose level of the subject using the electromagnetic wave.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Taiwan Patent Application No.101114805, filed on Apr. 25, 2012, in Taiwan Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to a method and device for noninvasivelydetecting a blood glucose level.

DESCRIPTION OF PRIOR ART

It is desired to provide a novel, noninvasive method to improve thecurrent, inconvenient blood glucose detecting method, having greatpotential to replace the current invasive detecting method and applyingto diagnose diabetes in clinical practice.

Diabetes mellitus (DM) refers to a group of common metabolic disordersthat share the phenotype of hyperglycemia. Depending on the etiology ofthe DM, factors contributing to hyperglycemia include reduced insulinsecretion, decreased glucose utilization, and increased glucoseproduction. The metabolic dysregulation associated with DM causessecondary pathophysiologic changes in multiple organ systems that imposea tremendous burden on the individual with diabetes and on the healthcare system. In the United States, DM is the leading cause of end-stagerenal disease (ESRD), non-traumatic lower extremity amputations, andadult blindness. It also predisposes to cardiovascular diseases. In2005, according to the World Health Organization, at least 346 millionpeople worldwide suffer from diabetes. Its incidence is increasingrapidly, and it is estimated that by 2030, this number will almostdouble. Diabetes mellitus occurs throughout the world, but is morecommon (especially type 2) in the more developed countries. Thediagnosis of diabetes includes an oral glucose tolerance test, fastingplasma glucose test, and random plasma glucose test.

Invasive Techniques

The most common invasive blood glucose detecting devices are glucosestrips along with hand-held glucose meters and implantable sensor, theformer one records glucose levels in blood drawn intravenously bypricking blood on skin via needles or micro-needles (such as: Exac-TechRSG, ABBOTT LABS; Amira AtLast, AMIRA MEDICAL; and Fast Take, LIFESCAN), and the later one measures glucose concentration subcutaneouslyby analyzing the interstitial water or tissue via microdialysis, opticalsensing such as fluorescence, or ultrasound transdermal glucosemonitoring (such as: Minimed Paradigm, MEDTRONIC and DexCom systems,DEXCOM) These approaches are short on health risks due to the sensorimplantation, infection, patient inconvenience, and measurement delaythat users will not be willing to use and will cause the risk ofinfection. Furthermore, the disposable test strip or the probes willcause an extra payment.

Non-Invasive Techniques

Recently, varied techniques were employed on non-invasive blood glucosedetecting device, such as reverse iontophoresis (ex. Gluco WatchAutomatic Glucose Biographer and Auto Sensors, CYGNUS INC.),bioimpedance measurement (Pendra, PENDRAGON MEDICAL LTD.), metabolicheat conformation, photoacoustic spectroscopy (US 20120172686, Jul. 52012), and dielectric spectroscopy. Utilized spectroscopic techniquesinclude: Raman (US 20050090750, Apr. 28 2005), fluorescence, as well astechniques using light from ultraviolet through the ultraviolet (200˜400nm), visible (400˜700 nm), near-IR (700˜2500 nm or 14286˜4000 cm-1)(U.S. Pat. No. 7,787,924, Aug. 31 2010; and US 20050010090, Jan. 132005), infrared (2500˜14285 nm or 4000˜700 cm-1), and microwave (>1 cm)(S. K. Vashist, Analytica Chimica Acta. 2012).

The above techniques still have some limitations or disadvantages formeasurements. Reverse iontophoresis technique requires a certain minimumduration and would be strongly interfered with sweating. The skinirritation observed in human subjects is the major drawback of thereverse iontophoresis technique. The measurement of Near-infraredspectroscopy (NIR) technique was sensitive to and easily being beinterfered by the physicochemical parameters, such as changes in bodytemperature, blood pressure, skin hydration, and concentration oftriglyceride and albumin. Besides, it is also sensitive to environmentalvariation in temperature, humidity, atmospheric pressure, and carbondioxide content. The mid-infrared spectroscopy technique which is basedon the same physical principle as NIR, has strong limitation of poorpenetration as light penetrates only a few micrometers inside the skin.The metabolic heat conformation has strong probability of interferingwith the environmental conditions such as temperature and humidity.

For Raman spectroscopy, the scattering effects and the re-absorption oflight in bio-tissues make the Raman signals hard to detect and requirelong spectral acquisition time. For Example, protein molecules produce abackground fluorescence signal that is often equal to or larger than theRaman signal itself. For these reasons, the suitable detecting area onbody for Raman measurement is the anterior chamber of the eye andaqueous humour. However, the above detecting areas are also sensitiveparts on the body that only allows for applying a safe dose of incidentirradiation power, and causes a poor detected result. Thefluorescence-based techniques need to inject fluorescent chemicals intohuman body. The detected signal will degrade during detecting time. Theoptical spectroscopies techniques apply ultra-violet or visible light toperform measurement, but the wavelengths of ultra-violet and visiblelight are relatively short that cause high scattering. For bioimpedancemeasurement techniques, the glucose detecting signal will change withdifferent detected individuals. Therefore, the bioimpedance measurementrequires additional calibration for the base signal level in skin andunderlying tissues among individuals. Beside, the bioimpedancemeasurement devices have multiple disadvantage and inconveniency forcalibration. For example, the commercial product, Pendra, needs tochanged the disposable detecting tape (Pendra tape) every 24 h. Afteronce calibration, the same detecting area needs 1 hour for equilibriumthat could be available for the next calibration, however the detectingresults still have poor correlation of only 35%. For another commercialproduct of the bioimpedance measurement devices, Clarke EGA, thedetecting results indicated 4.3% readings in error zone E, and the pooraccuracy also shows in the post-marketing validation study. The patientusing Clarke EGA must take rest for 1 hour for equilibration before thereading. The photo-acoustic technique needs strong pump power of lightto perform the measurement that may cause potential damage to thetissue. For the currently microwave spectroscopy techniques, thecurrently applying wavelength of the electromagnetic wave has a poorspatial resolutions. Because the tissue has a high dielectric constantat this wavelength that leads to the electromagnetic wave hard totransmit trough the tissue, and unable to achieve a transmissionmeasurement.

As described above, THz electromagnetic wave has potential to apply onnoninvasive blood glucose detecting device. But up to the present, thereis no available method or apparatus for measuring blood glucoseconcentration using absorption measurement of THz electromagnetic waves.Also, for the current non-invasive techniques, the glucose level is notmonitored directly via blood, but via interstitial fluid, tissue, orbody temperature that are correlated to blood glucose. Because theglucose level in tissue is easily to be affected, such as affected bymetabolic activity of tissue, medication, blood pressure, bodytemperature etc., the currently techniques need a further complicatedcalibrations for a higher accuracy detecting result. To overcome andimprove the disadvantage and inconveniency of current noninvasive bloodglucose detecting technique, the present invention provides anoninvasive blood glucose novel detecting method. The blood glucoseconcentration can be correctly obtained without further calibration forphysical parameters such as metabolic activity, medication, bloodpressure or body temperature, and without a complicated calibration forobtaining a higher accuracy detecting result.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee.

FIG. 1 is an illustration of a blood glucose detecting device in thepresent invention.

FIG. 2 is a related figure of the age and the corresponding bloodglucose level of the KK-A^(y)/Ta Jcl mouse.

FIG. 3 shows the device described in example 2.

FIG. 4 is an illustration of applying the device in the presentinvention to screen a subject, wherein 210 is electromagnetic wave, 220is a physical part of the subject and 221 is a blood vessel.

FIG. 5 is the electromagnetic wave absorption constant of a mouse ear.

FIG. 6 (a) is a photograph of a mouse ear and (b) is an electromagneticwave absorption 2D image of the measured mouse ear.

FIG. 7 (a) is an electromagnetic wave absorption 2D image of a diabetesmouse ear (KK-A^(y)/Ta Jcl) in 4^(th) week old age and (b) is anelectromagnetic wave absorption 2D image of the same mouse in the 5^(th)week old age.

FIG. 8 shows the device described in example 3.

FIGS. 9 (a)˜(d), respectively show the 2D electromagnetic waveabsorption constant image of 4^(th)˜7^(th) week old control mouse ear.

FIGS. 10 (a)˜(d), respectively show the 2D electromagnetic waveabsorption constant image of 4^(th)˜7^(th) week old diabetes mouse ear.

FIG. 11 shows a table of the weight, fasting glucose and glucosereaction in urine of the control and diabetes mouse.

FIG. 12 shows a blood glucose electromagnetic wave absorption constantregression curve.

FIG. 13 shows a device described in example 4.

FIG. 14 shows an electromagnetic wave absorption time domain signal.

FIG. 15 shows an electromagnetic wave absorption frequency domainsignal.

FIG. 16 shows blood glucose electromagnetic wave absorption constants ofpatients, with a high and normal blood glucose level.

FIG. 17 shows a correlating figure of the electromagnetic waveabsorption constant and the corresponding blood glucose level of humanblood.

SUMMARY OF THE INVENTION

The present invention provides a method for detecting a blood glucoselevel of a subject using an electromagnetic wave comprises the followingsteps: providing an electromagnetic wave using an electromagnetic wavesource; emitting the electromagnetic wave to a subject, wherein theelectromagnetic wave penetrates through the subject; using a detectingunit to receive and detect an intensity signal of the penetratedelectromagnetic wave; calculating the intensity signal of the penetratedelectromagnetic wave to obtain an electromagnetic wave absorptionconstant of the subject; comparing the electromagnetic wave absorptionconstant of the subject with data stored in a blood glucoseelectromagnetic wave absorption constant database; and obtaining a bloodglucose level of the subject. The present invention also provides adevice for detecting a blood glucose level of a subject using anelectromagnetic wave comprises: an electromagnetic wave source foremitting an electromagnetic wave to the subject; a detecting unit forreceiving and detecting the electromagnetic wave which penetratesthrough the subject; a converting unit for converting the penetratedelectromagnetic wave into an intensity signal of the penetratedelectromagnetic wave; and an analyzing unit for calculating thepenetrated electromagnetic wave to obtain an electromagnetic waveabsorption constant of the subject, and comparing the electromagneticwave absorption constant of the subject with data stored in a bloodglucose electromagnetic wave absorption constant database to obtain ablood glucose level of the subject.

DETAILED DESCRIPTION OF THE INVENTION

In feature, a different blood glucose level has individualelectromagnetic wave absorption ability. The present invention providesa novel blood glucose measuring device and method, using the highfrequency electromagnetic wave, THz electromagnetic wave, measuringtechnology to quantify the blood glucose level and building anoninvasive method for blood glucose measurement to thereby replace thecurrent invasive blood glucose detecting methods. The THzelectromagnetic wave provided by present invention has a reasonablepenetrating ability and safe operation power which overcomes thelimitations and disadvantages of prior arts. In general, the presentinvention provides a fast, accurately, and continuously detecting methodfor daily glucose level monitoring.

The present invention relates to a method for detecting a blood glucoselevel of a subject using an electromagnetic wave, comprises thefollowing steps:

-   -   (a) providing an electromagnetic wave using an electromagnetic        wave source;    -   (b) emitting the electromagnetic wave to a subject, wherein the        electromagnetic wave penetrates through the subject;    -   (c) using a detecting unit to receive and detect an intensity        signal of the transmitted electromagnetic wave;    -   (d) calculating the intensity signal of the penetrated        electromagnetic wave to obtain a electromagnetic wave absorption        constant of the subject;    -   (e) comparing the electromagnetic wave absorption constant of        the subject with data saved in a blood glucose electromagnetic        wave absorption constant database; and    -   (f) obtaining a blood glucose level of the subject.

In one embodiment of the present invention, the electromagnetic wavesource in step (a) the electromagnetic wave from the electromagneticsource is emitted to the subject via a waveguide unit, wherein thewaveguide guides the electromagnetic wave parallel penetrate through thesubject, which includes but not limited to a glass waveguide or apolyethylene (PE) waveguide.

The present invention is also related to a device 100 for detecting ablood glucose level of a subject 130 by an electromagnetic wave,comprises:

(a) an electromagnetic wave source 110 for emitting an electromagneticwave to the subject 130;

(b) a detecting unit 140 for receiving and detecting the electromagneticwave which penetrates through the subject 151;

(c) a converting unit 150 for converting the penetrated electromagneticwave 151 into an intensity signal of the penetrated electromagnetic wave152; and

(d) an analyzing unit 160 for calculating the penetrated electromagneticwave to obtain an electromagnetic wave absorption constant 161 of thesubject 130, and comparing the electromagnetic wave absorption constantof the subject with data saved in a blood glucose electromagnetic waveabsorption constant database 162 to obtain a blood glucose level 170 ofthe subject 130.

The device in present invention further comprises a waveguide unit 120for receiving the electromagnetic wave from the electromagnetic wavesource 110 and transmitting the electromagnetic wave to the subject 130,wherein the waveguide guides the electromagnetic wave to parallelpenetrate through the subject. In one embodiment a present invention,the electromagnetic wave source 110 includes but not limited to anaerial, microwave unit or millimeter wave unit. In one-embodiment, thedetecting unit 140 further comprises a Schottky diode 141, wherein theSchottky diode is a room temperature-operated detecting component,allowing the present invention able to measure the blood glucose levelof a subject under room-temperature.

In present invention, the intensity signal of the penetratedelectromagnetic wave includes a 1D, 2D signal, wherein the 1D or 2Dsignal further includes electromagnetic wave intensity or a detectinglocation. In one preferred embodiment of the present invention, the 2Dsignal is a 2D image which is obtained by scanning a physical part ofthe subject together in 2D using the electromagnetic wave source anddetecting unit. In other preferred embodiment, the 2D image is obtainedby scanning a physical part of the subject in 2D only using thedetecting unit.

In present invention, the device further includes a blood glucoseelectromagnetic wave absorption constant database 162, for saving thedata of blood glucose levels and their correlated electromagnetic waveabsorption constants.

The subject in present invention could be a living body, including ablood vessel(s) 221 passing through its physical part 220. In apreferred embodiment, the physical part 220 includes an ear(s), skin(s),finger(s), toe(s), lips or the skin linking between the fingers or toes.The electromagnetic wave 210 of the device can penetrate through thephysical part 220 and the inside blood vessel 221 of the subject. Inanother preferred embodiment, the subject can further be fixed using apair of films, wherein the films enable for the electromagnetic wave topenetrate, not absorb or reflect, through the subject.

The blood glucose electromagnetic wave absorption constant database inpresent invention provides a changing curve or a comparison table ofblood glucose electromagnetic wave absorption constants. In onepreferred embodiment, the changing curve or comparison table of bloodglucose electromagnetic wave absorption constants is a regressionfunction curve, and the formula of the regression function is:

y=a+bx  (1)

where y is blood a glucose level and x is an electromagnetic waveabsorption constant. Based on the above regression function, the data inthe comparison table of blood glucose electromagnetic wave absorptionconstants can be further calculated. In the present invention, the datain the blood glucose electromagnetic wave absorption constant databaseis selected from the changing curve or the comparison table of bloodglucose electromagnetic wave absorption constants.

The electromagnetic wave in the invention, generally, is a highfrequency or a tetrahertz electromagnetic wave. The frequency range ofthe electromagnetic wave in the present invention is about 1 GHz˜10 THz,a preferable range is 10 GHz˜1 THz, more preferable, in a range of 50GHz˜420 GHz.

The intensity signal of the penetrated electromagnetic wave can beconverted by applying a Beer-Lamber Law formula:

$\begin{matrix}{{{{Electromagnetic}\mspace{14mu} {wave}\mspace{14mu} {absorption}\mspace{14mu} {constant}\mspace{14mu} (\alpha)} = \frac{\ln \left( {P_{in}/P_{out}} \right)}{t}},} & (2)\end{matrix}$

wherein P_(in) is a power (or intensity) of the emitted electromagneticwave (background level), P_(out) is a power (or intensity) of thepenetrated electromagnetic wave and t is a thickness of the subject.Because different subjects may have different electromagnetic waveabsorption ability, it may need to enter a parameter(s) for correctingthe analyzing result of the present invention when calculating theelectromagnetic wave absorption constant of different subjects. Theparameter(s) described above includes but not limited to a thickness,skin or tissue electromagnetic wave absorption constant, or the bloodglucose level and its corresponding electromagnetic wave absorptionconstant of the detected subject.

EXAMPLES

The examples below are non-limiting and are merely representative ofvarious aspects and features of the present invention.

Example 1 Animal Model

The present invention used 4˜7-week-old BALB/cByJNarl mouse (purchasedfrom National Laboratory Animal Center in Taiwan) as a control model andused 4˜7-week-old KK-A^(y)/TaJcl mouse (purchased from CLEA Japan, Inc)as a type-2 diabetes model, which the blood glucose level raised duringageing, as shown in FIG. 2. The ear thickness of the mouse describedabove was 350 μm. The mouse was individually raised in a separated cage,and starved 8 hours before the experiment. Before experiment, the mousewas anesthetized using ketamine-xylazin (50 mg+15 mg/kg) by i.p.injection.

Example 2 Blood Glucose Detecting Device

In this example, a device 300, as shown in FIG. 3, used a CW Gunnoscillator module 301 as a electromagnetic wave source, a parabolicmirror 302 for focusing and transmitting the electromagnetic wave fromthe source through a PE film 303 and to a waveguide unit 304. Thewaveguide unit 304 adopted a highly flexible THz sub-wavelengthpolyethylene (PE) fiber with a diameter of 240 μm, a length of 33 cm anda substantially low attenuation constant (5×10⁻³ cm⁻¹). To improve thespatial resolution, behind the fiber output end, a bull's-eye metallicspatial filter with a subwavelength aperture (diameter of 200 μm) 305was intergraded to achieve both a high transmission power (10-foldhigher than transmission through a single bare aperture of the samesize) and near-field spatial resolution (240 μm<λ/4) beyond thediffraction limit.

The measurement frequency range of electromagnetic wave in this examplewas about 320˜420 GHz. 340 GHz was selected as a working frequency. Theelectromagnetic wave power on the surface of the mouse ear was about 1mW. A room-temperature-operated Schoktty diode detector 307 (VirginiaDiode, Inc, model WR-2.8, response time <5 μsec.) was used for receivinga transmitted electromagnetic wave 306. The detecting area was 10 mm×10mm and the imaging time is 3 mins/100×100 pixels. The preferred workingcondition of the present device was under room temperature 23° C. andwith about 50% humidity.

Operation of a Blood Glucose Detecting Device

First, without putting any subject on the device, the present exampleused the component of electromagnetic wave source (waveguide andbull's-eye metallic spatial filter with a sub wavelength aperture) toscan in 2D an area of 6 mm×4 mm in air and obtained a backgroundelectromagnetic wave absorption constant (or 2D image). The detectedimages of the following experiment in this example were normalized tothe background for correcting the angle-dependent bending loss. Afterabove steps, the mouse were anesthetized and moved to the detecting areaof the present device. The mouse ear was sandwiched by two acrylic filmsand fixed by a 6 mm×4 mm metallic aperture. The distance between thebottom of the mouse ear and the surface of the metallic bull's-eyestructure was about 250 μm. The device scanned the mouse ear using thebull's-eye metallic spatial filter with a subwavelength aperture 305 andthe detecting unit 307 by a 2D scanning method (FIG. 4), and obtained anelectromagnetic wave intensity 2D image. The 2D image and the backgroundlevel were then calculated using the Beer-Lamber Law to obtain a 2Delectromagnetic wave absorption constant image, as shown in FIG. 6( b).FIG. 5 showed the screening results of mouse ear with crossed bloodvessels by applying the present device using a serial electromagneticwave frequency. (FIG. 5 is not a background image, but a screeningresult of a living body.)

FIG. 6, including (a) and (b), was a photograph and its corresponding 2Delectromagnetic wave absorption constant image of the measured mouseear. In FIG. 6( b), in the mouse ear, the area with a passing bloodvessel had a higher electromagnetic wave absorption constant compared tothe surrounding tissue (α=10.5 mm⁻¹˜11.2 mm⁻¹). Besides, the subjectwith higher blood glucose level had higher electromagnetic waveabsorption constant. Therefore, the 2D electromagnetic wave absorptionconstant image could be used to recognize the position of the capillaryand the surrounding tissue in the ear.

Detecting Results of the Diabetes Animal Model

The present example used 4-week-old KK-A^(y)/TaJcl mouse as a type-IIdiabetes model. The detected 2 mm×2 mm electromagnetic wave absorptionimage of the same mouse with 4 and 5 weeks age were showed in FIGS. 7(a) and (b). The blood glucose electromagnetic wave absorption constantwas found to be increased from 14.5 mm⁻¹ to 16 mm⁻¹. It was also noticedthat the absorption constant of the surrounding tissues was alsoincreased, which suggested that the glucose content in the surroundingtissues was also increased.

Example 3 Blood Glucose Detecting Device

In the present example, a device 400 (FIG. 8) used a CW Gunn oscillatormodule 401 as a electromagnetic wave source, and a parabolic mirror 402for focusing and transmitting the electromagnetic wave from the sourceto a waveguide unit 403. The waveguide unit adopted a THz glasswaveguide with an inner-diameter of 9 mm, an outer-diameter of 13 mm, athickness of 2 mm and a length of 30 cm, wherein the glass waveguide hada substantially low attenuation constant (2×10⁻² cm⁻¹ @340 GHz). Toimprove the spatial resolution, a 300 um×700 um aperture was set infront of a Schoktty diode in a detecting unit 405.

The measurement frequency range of the electromagnetic wave in thisexample was about 320˜420 GHz. 340 GHz was selected as a workingfrequency. The electromagnetic wave power on the surface of a subject404, such as a mouse, was about 1 mW. A room-temperature-operatedSchottky diode detector (Virginia Diode, Inc, model WR-2.8, responsetime <5 μsec.) was used for receiving the penetrated electromagneticwave 306. The detecting area was 10 mm×10 mm and the imaging time is (3minutes)/100×100 pixels. The preferred working condition of the presentdevice was under room temperature 23° C. and with about 50% humidity.

Operation of Blood Glucose Detecting Device

First, without putting any subject on the device, the present exampleuse the component of the electromagnetic wave source and detecting unitto scan in 2D an area of 10 mm×10 mm in air and obtained a backgroundelectromagnetic wave absorption constant (or 2D image). After abovesteps, the mouse was anesthetized and moved to the detecting area of thepresent device. The mouse ear was sandwiched by two acrylic apertureswith a diameter of 9 mm. The distance between the mouse ear and thesurface of the detecting unit is about 2 mm. The device scanned themouse ear using the detecting unit 405 by a 2D scanning method, andobtained an electromagnetic wave 2D intensity image. The 2D image andbackground level were calculated using Beer-Lamber Law to obtain a 2Delectromagnetic wave absorption constant image.

The detecting results of the presenting device on different physicalparts of mouse (at 340 GHz) were: 11 mm⁻¹ of skin, 10 mm⁻¹ of tissue, 11mm⁻¹ of red blood cell, 11 mm⁻¹ of white blood cell and 12 mm⁻¹ ofwater. Besides, due to the resolution size (300 μm) was 2 times greaterthan the size of the capillary, the present invention would not belimited by the blood vessel size of the subject.

Detecting Results of the Control and Diabetes Animal Model

The present example detected the electromagnetic wave absorptionconstant of the 4-7-week-old normal and diabetes mouse. The 2Delectromagnetic wave absorption constant image of normal mouse showed inFIGS. 9 (a)˜(d), and diabetes mouse showed in FIGS. 10 (a)˜(d). FIG. 11showed the weight, the fasting glucose and glucose reaction in urine ofthe control and diabetes mouse. After calculated the above data into aregression curve (FIG. 12), the variation of the regression curve wasfound identically to the mouse blood glucose level. Therefore, thephysical blood glucose level could be obtained using the regressioncurve with electromagnetic wave absorption constant detected by thepresent invention.

Example 4 Blood Glucose Detecting Device

In the present example, the device 500 used terahertz time-domainspectroscopy (THz-TDS, FIG. 13). An electromagnetic wave source 510 useda Ti:Sapphire femtosecond laser 511 to emit a pulse laser to a beamsplitter 512. The pulse laser was separated by the beam splitter into apump beam and a probe beam. The pump beam was transmitted to anacousto-optic modulator (AOM) 513 and then focused onto a p-type InAscrystal 514 which converted the pump beam into a THz electromagneticwave. The THz electromagnetic wave was focused and transmitted to ameasured subject or sample (blood sample in this example) 530 by aparabolic mirror 520. Because a different blood glucose level isaccompanied by a different electromagnetic absorption coefficient, adifferent subject would have different response intensity to theelectromagnetic wave which penetrated through the subject. Using aparabolic mirror, the penetrated electromagnetic wave was transmittedand co-introduced with the probe beam through a silicon wafer 560 into aZnTe crystal 561 which converted the penetrated electromagnetic waveinto an optical wave. The optical wave and the probe beam produced anonlinear effect. The delayed optical path of the probe beam could beobtained by a micro-control translation stage 550, and used formeasuring the penetrated electromagnetic wave signal in any time pointto performed different intensity change. All optical waves finally weretransmitted through a convex 562, and the signal intensity of thoseoptical waves were detected by a balance detector 563 (Zomega—ABL100auto-balance detector). The detected signals were transmitted to asignal receptor 564 (Stanford research—SR844 Lock-in amplifier) toobtain a THz electromagnetic wave time domain signal (FIG. 14).

The electromagnetic wave absorption frequency domain signal (FIG. 15)was obtained by further calculating the information on THzelectromagnetic wave time domain signal by Fast Fourier Transform(formula 3):

$\begin{matrix}{{X_{k} = {\sum\limits_{n = 0}^{N - 1}\; {x_{n}^{{- {2\pi}}\; k\frac{n}{N}}}}},{k = 0},1,\ldots \mspace{14mu},{N - 1.}} & {(3),}\end{matrix}$

wherein x_(n) was a time domain signal, X_(k) was a frequency domainsignal and N was signal number (1024 in this example).

The present example further calculated the electromagnetic waveabsorption frequency domain signal using the Beer Lambert Law formulaand obtained as an electromagnetic wave absorption constant signal asshowed in FIG. 16. The results were summarized as below: the bloodsample with a higher glucose level had better electromagnetic waveabsorption ability than a lower one. Besides, the absorption constant ofsamples increased with the frequency of the detecting electromagneticwave.

Detecting Results of the Human Blood Sample

The present example detected 50 patient blood samples. FIG. 17 showedthat the electromagnetic wave absorption constants and the blood glucoselevels could perform a linear relationship (at 0.34 THz) with acorrelation coefficient of 0.872 (p<0.0001).

While the invention has been described and exemplified in sufficientdetail for those skilled in this art to make and use it, variousalternatives, modifications, and improvements should be apparent withoutdeparting from the spirit and scope of the invention.

One skilled in the art readily appreciates that the present invention iswell adapted to carry out the objects and obtain the ends and advantagesmentioned, as well as those inherent therein. The animals, processes andmethods for producing them are representative of preferred embodiments,are exemplary, and are not intended as limitations on the scope of theinvention. Modifications therein and other uses will occur to thoseskilled in the art. These modifications are encompassed within thespirit of the invention and are defined by the scope of the claims.

What is claimed is:
 1. A method for detecting a blood glucose level of asubject using an electromagnetic wave comprises the following steps: (a)providing an electromagnetic wave using an electromagnetic wave source;(b) emitting the electromagnetic wave to a subject, wherein theelectromagnetic wave penetrates through the subject; (c) using adetecting unit to receive and detect an intensity signal of thepenetrated electromagnetic wave; (d) calculating the intensity signal ofthe penetrated electromagnetic wave to obtain an electromagnetic waveabsorption constant of the subject; (e) comparing the electromagneticwave absorption constant of the subject with data stored in a bloodglucose electromagnetic wave absorption constant database; and (f)obtaining a blood glucose level of the subject.
 2. The method of claim1, wherein in step (b) the electromagnetic wave is emitted to thesubject via a waveguide unit.
 3. A device for detecting a blood glucoselevel of a subject using an electromagnetic wave comprises: (a) anelectromagnetic wave source for emitting an electromagnetic wave to thesubject; (b) a detecting unit for receiving and detecting theelectromagnetic, wave which penetrates through the subject; (c) aconverting unit for converting the penetrated electromagnetic wave intoan intensity signal of the penetrated electromagnetic wave; and (d) ananalyzing unit for calculating the penetrated electromagnetic wave toobtain an electromagnetic wave absorption constant of the subject, andcomparing the electromagnetic wave absorption constant of the subjectwith data stored in a blood glucose electromagnetic wave absorptionconstant database to obtain a blood glucose level of the subject.
 4. Thedevice of claim 3, further comprising a waveguide unit for receiving theelectromagnetic wave from the electromagnetic wave source andtransmitting the electromagnetic wave to the subject.
 5. The device ofclaim 3, wherein the intensity signal of the penetrated electromagneticwave comprises a 1D signal, 2D image.
 6. The device of claim 5, whereinthe 1D signal, 2D image includes electromagnetic wave intensity or adetecting location.
 7. The device of claim 3, wherein the analyzing unitcalculates the penetrated electromagnetic wave using a Beer-Lamber Lawformula to obtain an electromagnetic wave absorption constant of thesubject.
 8. The device of claim 3, wherein the subject is a living body,including a blood vessel(s) passing through its physical part.
 9. Thedevice of claim 8, wherein the physical part comprising an ear(s),skin(s), finger(s), toe(s) lips, or the skin linking between the fingersor toes.
 10. The device of claim 3 further comprises a blood glucoseelectromagnetic wave absorption constant database for storing data ofblood glucose electromagnetic wave absorption constants.
 11. The deviceof claim 10, wherein the database is a changing curve or a comparisontable of blood glucose electromagnetic wave absorption constants. 12.The device of claim 3, wherein the electromagnetic wave is a highfrequency electromagnetic wave and has a frequency range of 1 GHz˜10THz.
 13. The device of claim 12, wherein the frequency range of theelectromagnetic wave is preferable in a range of 10 GHz˜1 THz.
 14. Thedevice of claim 13, wherein the frequency range of the electromagneticwave is more preferable in a range of 50 GHz˜420 GHz.